A great deal of our knowledge about the neural mechanisms involved in spatial vision has come from studying the visual system of the cat. Neurophysiologists have examined in detail the spatial properties of neurons at various levels of the cat's nervous system, and attempts are being made to discover the patterns of neural connections which give rise to the remarkable degree of stimulus selectivity characteristic of these neurons. In addition, studies of the physiological effects of visual deprivation have provided important insights about the genesis of neural selectivity and into the possible neural bases of amblyopia and other visual disorders. As we continue to learn more about the neural mechanisms of spatial vision in the cat and about the crucial role of early visual experience, it becomes increasingly important to know in some detail the visual capacities of normal and specially-reared cats, as determined behaviorally. The proposed research, which represents an extension of previous work on this project, will employ the behavioural techniques of conditioned suppression and two-choice discrimination to study several problems concerning cat spatial vision: estimates of spatial frequency selectivity, role of central and peripheral retina in contrast sensitivity, behavioral analysis of X- and Y-cells, anisotropies in visual movement perception and contrast sensitivity in visually-deprived and strabismic cats. The general goal is to examine the extent to which spatial vision in the cat can be related to neural mechanisms within the animal's visual nervous system.